U.S. Pat. No. 9,002,420 BB discloses a watch worn by a user for interfacing with a mobile communication device. The watch includes an electronic display worn by user. The electronic display includes an interface for wirelessly interfacing with a mobile communication device carried by the user. The user interfaces with the electronic display to perform operations upon the mobile communication device. The watch also includes a mechanism to wirelessly establishing a voice channel with the mobile communication device for performing operations upon the mobile communication device. Additionally, the watch includes a mechanism for projecting directional sound to the user.
U.S. Pat. No. 8,655,004 BB discloses a monitoring system that can be placed proximate to the head or ear of a user. According to one embodiment, the monitoring system can be used with headphones, earbuds or headsets. The monitoring system can, for example, be used to monitor user activity, such as during exercise or sporting activities. The positioning of the monitoring system can also facilitate sensing of other user characteristics (e.g., biometric data), such as temperature, perspiration and heart rate. The monitoring system can also be used to control an electronic device. In one embodiment, the monitoring system facilitates user control of the electronic device using head gestures.